dtenedor commented on code in PR #39747:
URL: https://github.com/apache/spark/pull/39747#discussion_r1089460097
##########
sql/core/src/test/resources/sql-tests/inputs/string-functions.sql:
##########
@@ -231,3 +231,39 @@ CREATE TEMPORARY VIEW fmtTable(fmtField) AS SELECT * FROM
VALUES ('invalidFormat
SELECT to_binary('abc', fmtField) FROM fmtTable;
-- Clean up
DROP VIEW IF EXISTS fmtTable;
+-- luhn_check
+select luhn_check('4111111111111111');
+select luhn_check('5500000000000004');
+select luhn_check('340000000000009');
+select luhn_check('6011000000000004');
+select luhn_check('378282246310005');
+select luhn_check('6011000990139424');
+select luhn_check('1234567890');
+select luhn_check('4111111111111');
+select luhn_check('4111111111111112');
+select luhn_check('371449635398431');
+select luhn_check('371449635398432');
+select luhn_check('30569309025904');
+select luhn_check('30569309025905');
+select luhn_check('6011111111111117');
+select luhn_check('6011111111111118');
+select luhn_check('3530111333300000');
+select luhn_check('3530111333300001');
+select luhn_check('5105105105105100');
+select luhn_check('5105105105105106');
+select luhn_check('510B105105105106');
+select luhn_check('E105105105105106');
+select luhn_check('-5105105105105106');
+select luhn_check(5105105105105106);
Review Comment:
maybe add some cases with whitespace to show the resulting behavior?
##########
sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/stringExpressions.scala:
##########
@@ -3039,3 +3039,113 @@ case class SplitPart (
partNum = newChildren.apply(2))
}
}
+
+/**
+ * Function to check if a given number string is a valid Luhn number.
+ * Returns true, if the number string is a valid Luhn number, false otherwise
+ */
+@ExpressionDescription(
+ usage = """
+ _FUNC_(str ) - Checks that a string of digits is valid according to the
Luhn algorithm.
+ This checksum function is widely applied on credit card numbers and
government identification
+ numbers to distinguish valid numbers from mistyped, incorrect numbers.
+ """,
+ examples = """
+ Examples:
+ > SELECT _FUNC_('8112189876');
+ true
+ > SELECT _FUNC_('79927398713');
+ true
+ > SELECT _FUNC_('79927398714');
+ false
+ """,
+ since = "3.5.0",
+ group = "string_funcs")
+case class Luhncheck(child: Expression) extends UnaryExpression with
ExpectsInputTypes {
+
+ override def nullable: Boolean = false
+
+ override protected def withNewChildInternal(newChild: Expression): Luhncheck
=
+ copy(child = newChild)
+
+ /**
+ * Expected input types from child expressions. The i-th position in the
returned seq indicates
Review Comment:
no need to copy the method comment from the base `Expression` class
unchanged, you can just leave the method un-commented if it is simple and
self-explanatory.
##########
sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/stringExpressions.scala:
##########
@@ -3039,3 +3039,113 @@ case class SplitPart (
partNum = newChildren.apply(2))
}
}
+
+/**
+ * Function to check if a given number string is a valid Luhn number.
+ * Returns true, if the number string is a valid Luhn number, false otherwise
+ */
+@ExpressionDescription(
+ usage = """
+ _FUNC_(str ) - Checks that a string of digits is valid according to the
Luhn algorithm.
+ This checksum function is widely applied on credit card numbers and
government identification
+ numbers to distinguish valid numbers from mistyped, incorrect numbers.
+ """,
+ examples = """
+ Examples:
+ > SELECT _FUNC_('8112189876');
+ true
+ > SELECT _FUNC_('79927398713');
+ true
+ > SELECT _FUNC_('79927398714');
+ false
+ """,
+ since = "3.5.0",
+ group = "string_funcs")
+case class Luhncheck(child: Expression) extends UnaryExpression with
ExpectsInputTypes {
+
+ override def nullable: Boolean = false
+
+ override protected def withNewChildInternal(newChild: Expression): Luhncheck
=
+ copy(child = newChild)
+
+ /**
+ * Expected input types from child expressions. The i-th position in the
returned seq indicates
+ * the type requirement for the i-th child.
+ *
+ * The possible values at each position are:
+ * 1. a specific data type, for example, LongType, StringType.
+ * 2. a non-leaf abstract data type, for example, NumericType,
IntegralType, FractionalType.
+ */
+ override def inputTypes: Seq[AbstractDataType] = Seq(StringType)
+
+ /**
+ * Returns the [[DataType]] of the result of evaluating this expression. It
is invalid to query
+ * the dataType of an unresolved expression (i.e., when `resolved` == false).
+ */
+ override def dataType: DataType = BooleanType
+
+ /**
+ * Default behavior of evaluation according to the default nullability of
UnaryExpression. If
+ * subclass of UnaryExpression override nullable, probably should also
override this.
+ */
+ override def eval(input: InternalRow): Any =
Luhncheck.isLuhnNumber(child.eval(input))
+
+ /**
+ * Returns Java source code that can be compiled to evaluate this
expression. The default
+ * behavior is to call the eval method of the expression. Concrete
expression implementations
+ * should override this to do actual code generation.
+ *
+ * @param ctx
+ * a [[CodegenContext]]
+ * @param ev
+ * an [[ExprCode]] with unique terms.
+ * @return
+ * an [[ExprCode]] containing the Java source code to generate the given
expression
+ */
+ override protected def doGenCode(ctx: CodegenContext, ev: ExprCode):
ExprCode = {
+ defineCodeGen(
+ ctx,
+ ev,
+ c => {
+
s"""org.apache.spark.sql.catalyst.expressions.Luhncheck.isLuhnNumber($c)"""
+ })
+ }
+}
+
+object Luhncheck {
+
+ /**
+ * Function to check if a given number string is a valid Luhn number
+ *
+ * @param numberString
+ * the number string to check
+ * @return
+ * true if the number string is a valid Luhn number, false otherwise
+ */
+ def isLuhnNumber(numberString: Any): Boolean =
+ numberString match {
+ case number: UTF8String =>
+ val digits = number.toString
+ // Check if all characters in the input string are digits.
+ if (digits.forall(_.isDigit)) {
+ // Reverse the string so that we can use a foldLeft function
+ // and iterate through the digits in reverse order.
+ val (checkSum, _) = digits.reverse.foldLeft((0, false)) { case
((nSum, isSecond), d) =>
+ // Convert the digit character to an int.
+ val digit = d.asDigit
+ // Double the digit if it's the second digit in the sequence.
+ val doubled = if (isSecond) digit * 2 else digit
+ // Add the two digits of the doubled number to the sum.
+ val sum = nSum + (doubled % 10) + (doubled / 10)
+ // Toggle the isSecond flag for the next iteration.
+ (sum, !isSecond)
+ }
+ // Check if the final sum is divisible by 10
+ checkSum % 10 == 0
+ } else {
+ false
+ }
Review Comment:
```suggestion
}
```
##########
sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/stringExpressions.scala:
##########
@@ -3039,3 +3039,113 @@ case class SplitPart (
partNum = newChildren.apply(2))
}
}
+
+/**
+ * Function to check if a given number string is a valid Luhn number.
+ * Returns true, if the number string is a valid Luhn number, false otherwise
+ */
+@ExpressionDescription(
+ usage = """
+ _FUNC_(str ) - Checks that a string of digits is valid according to the
Luhn algorithm.
+ This checksum function is widely applied on credit card numbers and
government identification
+ numbers to distinguish valid numbers from mistyped, incorrect numbers.
+ """,
+ examples = """
+ Examples:
+ > SELECT _FUNC_('8112189876');
+ true
+ > SELECT _FUNC_('79927398713');
+ true
+ > SELECT _FUNC_('79927398714');
+ false
+ """,
+ since = "3.5.0",
+ group = "string_funcs")
+case class Luhncheck(child: Expression) extends UnaryExpression with
ExpectsInputTypes {
+
+ override def nullable: Boolean = false
+
+ override protected def withNewChildInternal(newChild: Expression): Luhncheck
=
+ copy(child = newChild)
+
+ /**
+ * Expected input types from child expressions. The i-th position in the
returned seq indicates
+ * the type requirement for the i-th child.
+ *
+ * The possible values at each position are:
+ * 1. a specific data type, for example, LongType, StringType.
+ * 2. a non-leaf abstract data type, for example, NumericType,
IntegralType, FractionalType.
+ */
+ override def inputTypes: Seq[AbstractDataType] = Seq(StringType)
+
+ /**
+ * Returns the [[DataType]] of the result of evaluating this expression. It
is invalid to query
+ * the dataType of an unresolved expression (i.e., when `resolved` == false).
+ */
+ override def dataType: DataType = BooleanType
+
+ /**
+ * Default behavior of evaluation according to the default nullability of
UnaryExpression. If
+ * subclass of UnaryExpression override nullable, probably should also
override this.
+ */
+ override def eval(input: InternalRow): Any =
Luhncheck.isLuhnNumber(child.eval(input))
+
+ /**
+ * Returns Java source code that can be compiled to evaluate this
expression. The default
+ * behavior is to call the eval method of the expression. Concrete
expression implementations
+ * should override this to do actual code generation.
+ *
+ * @param ctx
+ * a [[CodegenContext]]
+ * @param ev
+ * an [[ExprCode]] with unique terms.
+ * @return
+ * an [[ExprCode]] containing the Java source code to generate the given
expression
+ */
+ override protected def doGenCode(ctx: CodegenContext, ev: ExprCode):
ExprCode = {
+ defineCodeGen(
+ ctx,
+ ev,
+ c => {
+
s"""org.apache.spark.sql.catalyst.expressions.Luhncheck.isLuhnNumber($c)"""
+ })
+ }
+}
+
+object Luhncheck {
+
+ /**
+ * Function to check if a given number string is a valid Luhn number
+ *
+ * @param numberString
+ * the number string to check
+ * @return
+ * true if the number string is a valid Luhn number, false otherwise
+ */
+ def isLuhnNumber(numberString: Any): Boolean =
+ numberString match {
+ case number: UTF8String =>
+ val digits = number.toString
+ // Check if all characters in the input string are digits.
+ if (digits.forall(_.isDigit)) {
+ // Reverse the string so that we can use a foldLeft function
+ // and iterate through the digits in reverse order.
+ val (checkSum, _) = digits.reverse.foldLeft((0, false)) { case
((nSum, isSecond), d) =>
+ // Convert the digit character to an int.
+ val digit = d.asDigit
+ // Double the digit if it's the second digit in the sequence.
+ val doubled = if (isSecond) digit * 2 else digit
+ // Add the two digits of the doubled number to the sum.
+ val sum = nSum + (doubled % 10) + (doubled / 10)
+ // Toggle the isSecond flag for the next iteration.
+ (sum, !isSecond)
+ }
+ // Check if the final sum is divisible by 10
+ checkSum % 10 == 0
+ } else {
+ false
Review Comment:
```suggestion
false
```
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